Yotsuba Island, the place where the Marines of the 153rd Branch reside. It is located in the West Blue. The island has several towns, but the one that stands out the most is Shells Town. Shells Town is where the Captain that leads over the 153rd Branch lives, and altogether many other marines that are part of the 153rd Branch live there.

Shells Town has a execution side, where a pirate or convict gets tied up to a cross. There are times when they are given mercy, and will get released if they survive 30 days strapped to that cross without food, water, body movement or anything else besides their clothes. If not, the marines will use rifles to take the life of the convict.

The other towns are very similar to each other, and are nothing special. Houses made of wood, a local inn/tavern, some shops owned by villagers and a small time farm close by for the food supply.

The wildlife includes deer, bears, birds, foxes and wolves.